From hundreds of yards away, a Confederate sharpshooter carefully aimed his prized Whitworth, the crosshairs of its Davidson telescopic sight outlined against the ramparts of Fort Stevens in Washington, D.C. Through the scope—fitted to the left side of the stock—his eye scanned the ample crowd of Union soldiers and plucky civilians who had ventured by, hoping to observe warfare up close. Suddenly, the shooter’s attention shifted to a tall bearded man wearing a stovepipe hat, realizing it was that Yankee president, within easy range of his English-made precision rifle. As he prepared to fire, though, a Federal officer dragged Abraham Lincoln out of view.

This isn’t fiction. Lincoln actually came under fire on July 12, 1864, when Confederate Lt. Gen. Jubal Early’s Raid of Maryland reached Fort Stevens on the outskirts of the Union capital. Spent Whitworth bullets have been discovered in the vicinity, and we know sharpshooter rounds killed an officer a few feet away from the president. Had Lincoln been brought down, the Civil War may well have come to an entirely different conclusion, and an imported muzzle-loading rifle pressed into service by the Confederacy was the deadly tool that could have accomplished the job.

The Whitworth rifle claimed the lives of quite a few members of the Northern Army—artillerists, officers, and generals alike. But its impact in the war was limited, not by flawed design but because only a scant number managed to breach the formidable Union naval blockade of Confederate-controlled ports.

The story of this unusual shoulder arm begins in England with its namesake. Born in 1803, Joseph Whitworth showed a natural talent for mechanics at a young age. On completing school, he entered into an indentured apprenticeship in his uncle’s spinning mill with the intention of some day inheriting the business. He quickly mastered an understanding of the mill’s intricate machinery, often complaining about its lack of precision—an obsession that would distinguish him in time.